[libc-commits] [libc] [libc] Implement fallocate (PR #222843)

[Pavel Labath via libc-commits]

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@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of the fallocate, which is the
+/// base syscall wrapper for all fallocate dependent calls.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_FALLOCATE_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_FALLOCATE_H
+
+#include "hdr/errno_macros.h"
+#include "hdr/types/off_t.h"
+#include "src/__support/OSUtil/linux/syscall.h" // For syscall_checked
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h> // For syscall numbers
+
+namespace LIBC_NAMESPACE_DECL {
+namespace linux_syscalls {
+
+LIBC_INLINE ErrorOr<int> fallocate(int fd, int mode, off_t offset, off_t size) {
+#ifdef SYS_fallocate
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labath wrote:

When we do this, we also have an #else block with an #error, to make sure the code does not silently.. do nothing. However I think SYS_fallocate is old enough to be present on all systems we support, so you can just drop the #if.

https://github.com/llvm/llvm-project/pull/222843